A conventional stator core may be manufactured by stacking multiple plate members. Each plate member may include an annular portion and multiple projections. The multiple projections may be projected inward from the annular portion. Each annular portion may form a yoke. Each projection may form a tooth. The conventional stator core may need a lead wire to be inserted from the inside of the teeth when the lead wire is wound.
Another stator core may include a yoke and teeth, which are separate components. In this stator core, a lead wire may be wound around the teeth, and thereafter, the teeth and the yoke may be fixed together. This configuration of the stator core may enable the lead wire to be inserted to the teeth from the outside, when the lead wire wound around. Therefore, this configuration of the stator core may enable to employ, for example, a rectangular wire as the lead wires to form a high-density stator in a form of distributed winding, thereby to enable to reduce noise and oscillation.
As disclosed in Patent Document 1, in consideration of the teeth being a laminated object, this configuration of the stator core may need a bridge to tie ends of the teeth at the radially inside. For example, in a configuration with a large number is slots, each of the teeth may become thinner. In this case, crimping and welding may be hard to be implemented on the laminated object forming the teeth, without the bridge.
Patent Document 1
Publication of Unexamined Japanese Patent Application No. 2011-097769
In the configuration, in which the ends of the teeth are connected by using the bridge at the radially inside, magnetic flux may short-circuit through the bridge when the rotary electric apparatus is in operation. Consequently, disorder may occur in magnetic flux in a gap between the stator and the rotor. As a result, pulsation may occur in torque.
Pulsation in torque may decrease in a configuration in which the bridge is formed thinner as much as possible. In a case where the bridge is formed thinner as much as possible, precise manufacturing is required to press-form the teeth with the bridge from a plate member. In addition, reduction in rigidity of the teeth and the bridge may be concerned when the teeth and the bridge are equipped to the yoke. In this configuration, the teeth may be deformed due to reduction in rigidity.